What is spectroscopy and how does it determine the electromagnetic spectrum?

Hint: Spectroscopy commonly known as magnetic and electric spectroscopy is used in the branch of physics when we are dealing with electricity and magnetism. Initially the two were considered to be the same but both the electric field and magnetic field are quite dissimilar. Electromagnetic radiations have electric field vectors and magnetic field vectors which are perpendicular to each other and also to the direction of propagation.

Complete answer:
Spectroscopy refers to the study of the interaction of radiations with the matter. The radiations contain energy and the energy is radiated as the wave propagates.Electromagnetic radiations are characterized by their frequency or wavelength and they all move with the speed of light.

Spectra are observed when matter emits or absorbs light. When an object acts as a source of radiation, it is said to emit radiation. When radiation from another source interacts with matter, the matter is said to absorb radiation. When the radiation falls on the matter it can be reflected or absorbed.

By studying the spectra of the radiations, we can arrange them in increasing or decreasing order of their wavelength or frequency. Thus, we get an electromagnetic spectrum. For example, Radio waves, microwaves, infrared waves, visible radiation, X rays, gamma rays are arranged in increasing order of their frequency in the electromagnetic spectrum.

Note: Spectroscopy helps in determining the structure of the matter. One such use is X ray diffraction for determining the structure of the constituent atoms or molecules. Other widely used techniques are NMR or Magneto telluric oscillations and all these methods use electromagnetic radiations. Using spectroscopy, chemists can identify different species present in a sample or "map out" the structure of a molecule.